This invention is related to the subject matter of U.S. Pat. No. 4,375,021 entitled "Rapid Electric Arc Extinguishing Assembly in Circuit Breaking Devices Such As Electric Circuit Breakers," issued Feb. 22, 1983 and assigned to the Assignee of the instant invention, which application is incorporated herein for purposes of reference. This invention relates in general to the magnetic motoring assembly shown at FIG. 1 in the aforementioned Patent and, in particular, to the insulating material forming a coating and filling the gaps existing between the plates of magnetic material of the side magnetic assembly, in such a manner as to form an arc as described in the aforementioned patent, and also to the arc motivating assembly shown at FIG. 12, particularly the material forming the two columns flanking the side assembly.
One problem described within the aforementioned patent was that the insulating material forming the columns of the assembly, must satisfy two contradictory requirements, namely, a high electrical insulation and a high arc resistance while at the same time contribute substantially to the blow out and extinction of the arc by the vaporization of gases. Unfortunately, the insulating substances known in the art will either provide the high insulation coefficient and high arc resistance, while slightly contributing to the blow out and extinction of the arc, or they vaporize and contribute to the blow out and extinction of the arc but are incapable of maintaining their properties after exposure to the arc.
One of the main objects of this invention is to provide the insulation which is necessary between the contacts of a circuit breaker when the contacts are open and, at the same time, to develop effective blow out and extinction of the arcing between the contacts when opened.